Multiresonant Spectroscopy and the High-Resolution Threshold Photoionization of Combustion Free Radicals
Author | : |
Publisher | : |
Total Pages | : 404 |
Release | : 2005 |
ISBN-10 | : OCLC:68506893 |
ISBN-13 | : |
Rating | : 4/5 (93 Downloads) |
Book excerpt: This report describes the results of a program of research on the thermochemistry, spectroscopy and intramolecular relaxation dynamics of the combustion intermediate, HCO. We prepare this radical from acetaldehyde as a photo-precursor in a differentially pumped laser-ionization source quadrupole mass spectrometer. Using a multiresonant spectroscopic technique established in our laboratory, we select individual rotational states and overcome Franck-Condon barriers associated with neutral-to-cation geometry changes to promote transitions to individual autoionizing series and state-resolved ionization thresholds. Systematic analysis of rotational structure and associated lineshapes provide experimental insight on autoionization dynamics as input for theoretical modeling. Extrapolation of series, combined with direct threshold-photoelectron detection, yield precise ionization potentials that constitute an important contribution to the thermochemical base of information on HCO.